If Crystalis has a battery-backed save system it's news to me. And I've beaten the game on the original hardware.
Re:Nintendo re-releases NES as mini console
by msbarnett on Sunday July 17, 2016 @03:54PM
(#12111505)
Crystalis absolutely has a save/continue system. You can see some guy demonstrating the save system in crystalis in this video, complete with save functionality: https://m.youtube.com/watch?v=73za3LHWzwk
Are you thinking of some other game?
And while overall most NES games didn't use a battery, many of the most popular ones (many of the ones included in this thing, in fact) do need a working battery. Final Fantasy, both zeldas, startropics, tecmo bowl, crystallis, kirby's adventure...